IUI, trigger shot and one follicle

Kerstin
We have our first ever IUI tmrw at 7 am!!! Went in today and saw one great follicle 25 mm!!! Dr called and said I already started to surge, and to do the trigger shot immediately and come in tmrw to do IUI, anyone every get pregnant on first IUI and or only one follicle?! Would love to here some  responses!!! Baby dust to all 😘😘😘😘😘💗💗💗💗